Healthcare-acquired infections (HAIs) cause significant morbidity and mortality with the highest infection rates found in the intensive care unit (ICU). Identification of risk factors for HAIs may reduce infection occurrence and patient mortality. While the problem of HAIs is complex and multi-factorial, one potential risk factor is environmental contamination with potentially pathogenic microorganisms (PPMs). Contaminated objects used in direct patient care may become vectors, transmitting PPMs, and resulting in increased risk of HAIs. Toothbrushes used in patient care may be at risk for contamination because they are stored in the patient care environment (environmental contamination) and used repeatedly without decontamination (leading to repeated autoinoculation of a patient harboring PPMs in the oral cavity). Critically ill patients represent a vulnerable population at higher risk of colonization by PPMs due to decreased host defenses and changes in their normal oral physiology. Toothbrush contamination as a source of PPMs in the ICU has not been explored. Examining the toothbrush as a potential source of PPMs in the ICU is important for assessing potential risks and benefits of oral care and informing nursing practice for critically ill patients. The primary aim of this study is to describe environmental factors associated with toothbrush contamination in the ICU. A secondary aim is to describe the relationship between toothbrush contamination and oral colonization in critically ill adults. This proposal will use a cross sectional design to examine the ICU environment, toothbrush contamination and the presence of PPMs in the patient's oral cavity in 100 paired samples of ICU subjects and the toothbrushes used in their care over 72 hours. Subjects will be enrolled from cardiac, medical, neurological and surgical- trauma ICUs at a university teaching hospital. At study enrollment a baseline oral culture will be obtained and a new sterile toothbrush provided. Subjects will be randomly assigned to one of three toothbrush time in environment (TIE) groups for post enrollment data collection (24, 48 and 72 hours). At 24, 48 or 72 hours (by TIE group), toothbrushes will be observed (for location in patient environment, bedside storage container, contact with other articles) and measured for moisture. Using standard microbiological methods, PPMs will be cultured from the toothbrush and oral cavity of each patient. Concordance of oral and toothbrush isolates will be examined by molecular strain typing using Multi Locus Sequence Typing (MLST). Descriptive statistics, linear regression, ANOVA, and multivariable logistical regression will be used to evaluate the relationships among key variables. The results obtained from this proposal may help to reduce toothbrush contamination which may positively impact patient outcomes by reducing risk of exposure to PPMs.